Shock absorber



F@h-Z5, 3936. D. FUNSTON 2,932,124

SHOCK ABSORBER Filed Aug. 22, 1954 INVENTOR FREDERICK D. FUNST ATTORNEY Patented Feb. 25, 1936' UNITED STATES PATENT OFFICE SHOCK ABSORBER Application August; 22, 1934,,ScrialNo. 749,948

15 Claims. (Cl. 188"88)' This invention relates to improvements in hydraulic shock absorbers.

It is among theobjects of the present invention to provide a hydraulic shock absorber capable of being adjusted automatically to vary its resistance to relative movements between the frame and axle of a vehicle in response to and proportionately withaccelerations in the vertical movements of the frame.

A further objectof the present invention is to provide a hydraulic shock absorber capable of being adjusted automatically proportionately with accelerations in the vertical movements of the shock absorber and manually to vary the effective control of the automatic adjusting means.

Further objects and advantages of' the present invention may be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. l is a fragmentary side View of. a vehicle chassis, with wheels omitted, a shock absorber embodying the present invention being shown applied thereto.

Fig. 2 is a fragmentary sectional view of the shock absorber showing the various elements and their fluid and mechanical connections.

Referring to the drawing, the numeral designates the frame of the vehicle which is supported upon the vehicle axle 2|. by springs 22, only one being shown. The shock absorber designated as a whole by the numeral 23-comprises a casing 24, providing a fluid reservoir 25 and a cylinder 25'. One end of this cylinder is shown closed by an integral wall 21, the other being provided with a cylinder head 28threadedly received by the cylinder and having a gasket 29 to prevent fluid leaks at this end of the shock absorber.

Within the cylinder a piston 30 is slidably supported, said piston having oppositely disposed piston heads 3| and 32, the! first forming what may be termed the spring compression control chamber 33, the latter the spring rebound control chamber 34. A space 35 is provided intermediate the piston heads 3! and32, the end walls of this space having wearpieces 36. The freev end 3'! of the rotatable cam element 38 extends into the space 35 and engages the wearpieces 36. This rotatable cam element is attached to the operating shaft 39 of the shock absorber, which shaft is journalled in housing 24 transversely thereof, one end extending outside the shock absorber. and having the. shock absorber operating arm 43 secured thereto. The free end of this arm is swivelly secured to one end. of a link 41, the opposite end of which is anchored to the axle 2| by the clamping member 42.

From this it may be seen that the axle 2|. is operatively connected with the piston and any relative movements between the axle and the frame will cause reciprocation. of the piston, the frame having the casing 24 attached thereto in any suitable manner.

Each piston head, 3| and 32 is provided with a through-passage havingfiuid flow. control devices therein, and. inasmuch as both piston heads are similarlyequipped, for the sake of brevity only one will be. described detailedly.

The passage through the cylinder head 3] is designated by the numeral 45. In it there is provided an annular sharp-edge ridge 46 forming a valve-seat for the intake valve 47, which valve has a tubular body portion 48; This valve is urged into yieldable-engagement with the seat 46 by a spring 49, one end ofwhichengages the valve, the other abutting against a ring-member 50. seated in a groove-in the interior surface of the piston head passage. Thetubular body portion 48 of. the

intake valveslidably supports the stem 5|, which stemhas, the valve 52zin the form of a head attached, at its one end, the opposite end having an abutment washer 53 secured thereto. A spring 54, interposed between theabutment washer 53 and the intake valve 41, yieldably urges the stem 51 sothat its valve head 52 normally engages the outer end surface of. the intake va1ve'4l. A groove 55 in the stem. 5| normally lies within the confines of the intake valve 41, but provides a fluid passage through said valve 41 when pressure moves the valve-head 52- from engagement therewith.

The aforedescribed fluid flow control device in each piston head operates as iollowsz.

In response to the movement of the axle 2| toward the frame 20the mechanical connections between. the axle and the piston will cause said piston to be moved toward the left and consequently the fluid within the reservoir 25 will urge the intake valve 41 of the piston head 32 from its seat to establish a substantially free flow of fluid from themeservoir 25 through the piston passage of piston head 32' into the, spring rebound control chamber 34. This. same movement of the piston will exert a pressure upon: the fluid within Y the spring compressionv control chamber 33, which pressure,v when attaining a, predetermined degree, will. move valve-head 52 from engagement with intake valve 41-, against the effect of spring 54, to establish. a restrictedflow of fluid *control devices of the shock absorber,,to be described, becoming effective to provide fluid flow control before such pressure is attained. It will of course be understood that upon the reverse movement of the piston, that is to the right" as regards Fig. 2, which movement results when the axle 2| and frame 20 of the vehicle separate, the intake valve 4'! of piston head 5| will be actuated to establish a substantially free flow of fluid into the spring compression control chamber 33, while the pressure exerted upon the fluid within the spring rebound control chamber 34 will, when attaining the proper degree, actuate the pressure release valve 52'of .the piston head 32 to provide for a restricted flow of fluid from chamber 34 through the pisten head 32 into the reservoir 25. Both these restricted flows through the piston heads 3| and'32 will resist piston movement and consequently the relative movements between the axle and frame of the vehicle will likewise be resisted.

The fluid flow control devices adapted to become eifective before the .fiuid flow control devices of the piston 30 will now be described.

In Fig. 2 it is seen that, extension 60 is provided in the casing, being threadedly received thereby to permit assembly of parts. Between the main casing 24 and this casing extension 60 there is formed a chamber 6| in which a pivot pin 62 is provided upon which an arm 63 is 'pivotally supported. Equally spaced on each side of the pivot pin 62 and attached to the arm are contact blocks 64 and 65, whose functions will be described hereinafter. A n inertia weight element 66 is rigidly secured to one end of the pivoted arm 63, this weight being held in suspension by a spring 61 interposed between the arm 63 and the casing portion 60. A recess 68 is provided in the casing portion 60, this recess 'fOrming the dashpot cylinder, the piston of the dashpot designated by the numeral 69 being slidably carried within said cylinder.

Beneath this cylinder 66 the casing 60 has a cylindrical recess I0 which is in communication with the chamber in cylinder 68 beneath the piston 69 through three passages II, I2, and 13, the passage 7| being the largest, the passage 131 being the smallest. The cylindrical opening 10 is in communication with the chamber 6| through a passage I4 provided in the casing. Communi= cation between the passages II, I2 and I3 and the passage l4 via the cylindrical opening I0 may be cut oif by a plug I5 which is rotatably sup ported within the cylindrical opening I0 and (which extends to the outside of the shock aband 'II, dependent upon the eperation of the lever 16 secured to the plug I5. A link 'IB,'connected to said lever I6,may lead to any suitable place in the vehicle whereby the operator of the vehicle may adjust the plug 15 from his position within the vehicle while it is in. operation, to

"vary the control of the shock absorber over the which is similar to recess i 8!.

interior of the valve=stem H6.

frame and axle movements of the vehicle. This mechanism including the piston 69 and the manually operated valving plug I5 comprises the governor by which the shock absorber is adjusted to vary its control as stated.

A duct 88 leads from the spring compression control chamber 33 into a recess 8| formed in the casing extension 09. This recess is in communication with another recess 82 by a passage 83 of lesser diameter than eitherrecess 8| or 82.

Recess 8| has a smaller diameter portion 96, thus.

providing a shoulder 34 against which a valveseat member 85 is urged by spring 86 which.

spring is interposed between said valve-seat member and a plug 87 threadedly received by the outer open end of recess 8|. This valve-seat member 85 has a central tubular portion 88 prestem 9| is a small orifice 92'which provides'corn munication between thechamber 96 above the valve seat member 85 and the interior of the tubular valve stem 9|. The tubular valve stem 9| has an enlarged head 93 slidably supported Within the recess 82, said enlarged head 93 forming a piston reciprocative in the recess 82 and engaged by one end of a spring 94, the other end engaging the screw plug 95 threadedly received by the open end of the recessSZ. Spring 94 normally urges the piston 93 and'its valve stem 9| so that the closed end 90 or" thevalve stem is yieldably maintained in engagement with the annular sharp edge valve-seat 89.

compartments formed in recess 8| on opposite sides of the valve-seat member 85.

Another recess isprovided in the casing extension 60, this recess being designated by the numeral I00. It is in communication with the compartment 96 about the valvestem 9| through a passage 98. Normally this communication between compartment 95 and recess I00 is cut off by a. check-valve |0| which is yieldably urged to shut off such communication by a spring |02 interposed between the valve I 0! and a nipple plug I03 threadedly received by the open end of recess I00 and adjustable relatively to the casing 60 so as to permit changing of the tension of spring I02. To this nipple plug I03 a conduit 594 is attached which conduit leads to a passage H in the casing 24, said passage opening into the spring rebound control chamber 34.

A conduit I I0 leads from the recess I99 on the discharge side of valve Iill to another recess III, In this recess a valve seat member having an annular valve seat I I2, similar to the valve seat 89 of the valve seat -member 85, ismaintained in normal position by a spring H3. This valve seat H2 is engaged by the closed end H5 of the valve-stem H6, which valve-stem is slidably carried in the passage H'I leading from recess III to the recessj I8. Valve stem H6 has an orifice H9 which provides communication between the compartment I20 surrounding the lower end of the valve-stem H6 and above the valve-seat" member H2, and the Like valveestem 9|, valve stem H6 has an enlarged head portion |2I forming a piston slidably supported within The compartment I20 This nor- 'mally shuts off communicationbetween the two is in. communication witha recess I 30 through a passage I3I, communication between the passage I3I andthe recess I30 being normally shut off by a check-valve I32 urged into its normal position by spring I33 interposed between said valve and a screw plug I34 threadedly received in the outer open end of the recess I30. This recess I30 is also in communication with the recess 8| through a passage I36, and inasmuch as passage 8| is in communication with chamber 33 through the conduit 80, it may be said that recess I30 is also in communication with said chamber 33.

In order to eliminate a' hydraulic lock beneath the valve pistons 93 and I2I, a fluid passage I is provided connecting the two recesses 82 and H8 beneath said pistons.

The chamber in the recess 82 between the piston 93 and the screw plug 95 has a passage |5I leading therefrom communicating with a passage I52. This passage I52 terminates in a cross passage I53 and normally communication between passage I52 and this cross passage I53 is cut off by the gravity valve I54. This valve is in direct alignment with the contact block 64 on the pivoted lever 63. Similarly the space in recess H8 between piston IZI and plug I23 has a recess I leading therefrom into the passage IEiI, said passage I6| terminating in a cross passage I62. Communication between passage |6I and cross passage IE2 is normally shut off by the gravity Valve I63 which is in direct alignment with the contact block 65 also carried by the arm 63;

As has been mentioned heretofore, when the axle 2| approaches the frame 20, mechanical connections between the axle and the piston 30 moves the piston toward the lever past the piston head 3| to exert a pressure upon the fluid within the spring compression control chamber 33. This will force the fluid from said chamber through the conduit 30 and into the recess 8|. From here the fluid flows through the valve seat member against the closed end of the valve member 9|. When the pressure of this fluid flow is suflicient it will move the valve-stem 9| against the effect of the spring 94 to permit fluid to flow through the valve seat member 85 past the closed end 90 of the valve into the chamber 96 from where said fluid will flow into the passage 98 and engage and move valve I0| from its seat to establish a flow from passage 98 into the recess I9I from where the fluid will flow through conduit I04 and passage I05 into the spring rebound control chamber 34. Valve I 0| has a predetermined spring load so that it restricts the fluid flow from the compartment 96 and thus creates a pressure therein which causes the fluid to flow from compartment 96 through the orifice 92 in the valve-stem 9| into the interior of said valve-stem and from there into the recess 82 above the piston 93. Normally this fluid will flow from recess 82 through passages I5| and I52, lifting the valve I54 against gravity and thus permitting the fluid to flow from passage I52 through the cross passage I53 into the chamber 6| which is in communication with the reservoir 25 by the passage 290 in casing 24. It will be seen that changing of the tension of spring I02 upon valve I 0| will vary the restriction to the fluid flow from passage 98 into the recess I00 and consequently the pressure of this fluid in compartment will be varied, similarly the pressure in the recess 82. Now, if the body carrying frame 20 should move downwardly at an accelerated rate, causing relative movement between the casing 24v and the inertia weight 65, said inertia weight 66 will cause the lever 63 to move about its pivot pin 62 in a counter-clockwise direction, resulting in the contact block 64 engaging valve I54 urging it downwardly toward the passage I52. to restrict the fluid flow from said passage into the cross passage I53. The flow from passage I52 being restricted will cause an increase in the pressure of the fluid within recess 82 and this pressure acting upon the enlarged piston 93 will move said piston downwardly in the recess 82; resulting in a downward movement of the valve-stem 9| and consequently a nearer approach of the closed end 90 thereof to the valve seat 89. This increases the restriction to the fluid flow through the valve-seat member 85. proportionately to the acceleration of the movement of the body carrying frame 20 downwardly and consequently the resistance to this downward movement of the frame 20 is in- 7 creased proportionately to its acceleration.

On the other hand if the piston 30 is moved toward the right as a result of the separating movement between the frame and axle of the vehicle, the fluid in chamber 84 will be forced out of said chamber through the passage I05 and conduit I04 into chamber I00. From here the fluid will flow through passage IIIl into recess III against the closed end N5 of the valve II6. This fluid pressure will move the valve against the effect of spring I22, resulting in a flow of fluid through the valve-seat member II2 into the compartment I20 thence through passage I3I against the valve I32 which will be moved from its seat to permit the fluid to flow into the recess I30. From here the fluid will flow through passage I36 into the recess BI and then through conduit 80 into the spring compression control chamber 33, Like in the case'of valve IOI, valve I32 will create a pressure within compartment I20, this pressure build-up resulting in a flow of fluid from compartment I20 through the orifice II9 into the interior of valve-stem IIE, from where the fluid will flow into the recess I22. After the fluid has reached the recess I22 above piston I2I it flows through passages I60 and I6! against the valve I63, lifting this valve against gravity to establish a flow through the cross passage I92 into the compartment 6|.

In case the upward movement of the body carrying frame 20 is accelerated a predetermined degree, a relative movement between the shock absorber casing 24 and the weight 66 obtains, causing the weight 66 to move the arm 63 clockwise about its pivotal support 62 whereby contact block 65 will engage valve I63 to urge it toward passage I6I and restrict the fluid flow therefrom. This restriction causes a pressure build-up within the recess I22, resulting in a downward movement of the piston |2I and its valve-stem II 6, causing the fluid flow through valve-seat member I I2 to be restricted and consequently resisting the movement of the piston 30 toward the right.

Thus it may be seen that, in response to accelerations in the movement of the body-carrying frame member 20 the weight 66 will act to restrict fluid flows, which restriction causes adjustments of the main fluid flow control devices, resulting in a similar restriction to the main fluid flows. This restriction to the main fluid flows will increase the effective resistance of the shock absorber to relative movements between the body carrying frame and the axle 2| of the vehicle proportionately with the accelerations in I the movement of said body carrying frame 20.

From the aforegoing descriptionof thelmain fluid flow control. devices which include valve acting upon the ends 90 and H2 of the valve stems 9| and H6 respectively.

If the operator finds that the resistance offered by the shock absorber is too great, then he moves the link 18 connected with lever 16 to rotate plug 15 so that one or more of the passages H, 12, and 13 are closed. This increases the resistance to the escape of fluid from beneath the dashpot piston 69 attached to the weight 66 and consequently increases the retarding effect of the dashpot to the weight movement, thereby requiring a greateracceleration in the movement of the body carrying frame before it becomes effective to increase the control over' the -main fluid flow. If, on the other hand, the operator desires a greater resistance by the shock absorber to body movements, then he moves the lever 16 so that more of the passages H1, 12 or T3 are uncovered, increasing the fluid flow capacity between the space beneath the dashpot piston69 and the exhaust passage 14 thus permitting a freer movement of the weight 66. Such an adjustment will permit theweight to become effective to increase the resistance at comparatively lesser accelerations in the movement of the body carrying frame 20 and thus the shock absorber will be adjusted to offer a greater resistance to such frame movements.

Applicant has thus provided a shock absorber adapted automatically to adjust itself proportionately with the accelerations in the vertical movements of the body carrying frame 20. He has also provided a manual control which may be actuated by the operator as he drives the vehicle for purposes of increasing or decreasing the effective resistance offered by the shock absorber against such body movements.

While the embodiment of the present invention constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A hydraulic shock absorber comprising, in combination, a casing providing a fluid displacement chamber; fluid pressure actuated means for controlling the flow of fluid from said chamber; inertia mass controlled means for regulating fluid flow to vary the controlling effect of the aforementioned means; and manually adjustable means for varying the effect of the inertia mass controlled means.

2. A hydraulic shock absorber having means for circulating a fluid; fluid pressure actuated means for controlling said fluid circulation; an inertia mass controlled means for regulating the fluid pressure to vary the regulatory effect of the first mentioned means; means for retarding the operation of the inertia mass controlled means;

and a manually adjustable member for varying the effect of the retarding means.

3. A hydraulic shock absorber having means for circulating a fluid; a valve adapted to be actuated by fluid pressure in either direction for controlling said fluid circulation; means adapted tocontrol fluid flow for adjusting said valve to vary its effect; an inertia weight for actuating said means; means for retarding the movements of the inertia weight; and a manually adjustable member for varying the retarding effect of the last mentioned means.

4. A hydraulic shock absorber having means for circulating fluid; inertia mass controlled means including a fluid pressure multiplying valve for regulating said fluid circulation; and a manually adjustable governor for varying the effect of said inertia mass controlled means.

5. A hydraulic shock absorber having means for circulating fluid; an inertia mass regulated fluid flow control device including a fluid pressure multiplying valve for controlling said fluid circulation; a hydraulic governor for retarding the operation of the device and manual means for varying the retarding effect of said hydraulic governor.

6. A hydraulic shock absorber having means for circulating fluid; inertia mass controlled means including a valve adapted to be operated in either direction by fluid pressure for regulating said fluid circulation; a dashpot for retarding the operation of the inertia mass controlled means; and manual means for varying the retarding effect of the dashpot.

7. A hydraulic shock absorber having means for circulating'fluid; a valve adapted to be actuated by fluid pressure to permit said fluid'circulation; a second valve actuated by'an inertia weight for adjusting the first mentioned valve to vary its control of the fluid flow; means for retarding the movement of the inertia weight; and a manually adjustable member for varying the effect of the retarding means.

8. A hydraulic shock absorber'having means for circulating fluid; a spring loaded valve adapted to be actuated by fluid pressure to provide two paths of fluid flow; an inertia weight actuated valve adapted to regulate the fluid flow in one of said paths to adjust the spring loaded valve to vary the fluid flow in the other path; and manually adjustable means for varying the effect of the inertia weight actuated valve,

9. A hydraulic shock absorber having means for circulating fluid; a pressure release valve adapted to permit fluid circulation through two paths in response to fluid pressure; means for restricting the fluid flow through one of said paths; an inertia mass actuated valve for regulating the fluid flow through the other path to effect adjustment of the pressure release valve; and a manually adjustable governor for controlling the operation of the inertia mass actuated valve.

10. A hydraulic shock absorber having means for circulating fluid; a spring-loaded valve adapted tobe actuated by fluid pressure to permit fluid circulation through two paths; a spring loaded valve for restricting the fluid flow through one of said paths; means on said first valve adapted to be actuated by fluid pressure to adjust said valve to vary its restriction to fluid flow; a valve for controlling the fluid flow through the other 7 of said paths; an inertiaweight for actuating said last mentioned valve; .a governor for controlling the movements of the inertia weight; and

manual means for regulating the governor.

11. A hydraulic shock absorber having means for circulating a fluid; fluid flow control devices for regulating said fluid circulation, certain of said devices being actuated by fluid pressure in veithertdirection and another by an inertia weight;

a hydraulic governor connected with the weight for controlling its movements in both directions; and a manually adjustable valve for regulating the flow of fluid of the governor to vary its efiect upon the inertia weight movements.

12. A hydraulic shock absorber having means for circulating a fluid; a valve actuated by fluid pressure in either direction for regulating said fluid circulation; a check valve for controlling the fluid flow that actuates the first mentioned valve in one direction; an inertia weight for actuating said check valve; a hydraulic dashpot for retarding the movement of the inertia weight in either direction, the movable member of said dashpot is connected to the weight; and a manually adjustable valve for controlling the flow of fluid into and out of the dashpot to vary the operation of the weight.

13. A hydraulic shock absorber having means for circulating a fluid; means normally preventing fluid circulation but actuated by fluid pressure to permit circulation and also to increase its restriction to fluid flow; means actuated in response to accelerations in the movements of the shock absorber vertically to vary the effect of said first mentioned means; a governor for retarding the movements of the last mentioned means; and a manually adjustable member for varying the retarding effect of the governor.

14. A hydraulic shock absorber having means for circulating a fluid; means including a valve adapted to be actuated in either direction by fluid pressure and an inertia weight actuated valve for restricting said fluid circulation in response and proportionately to accelerations in the vertical movements of the shock absorber; a governor for regulating said means; and a manually adjustable member for varying the effect of the governor upon said means.

15. A hydraulic shock absorber having means for circulating a fluid; means including a valve adapted to be actuated in either direction by fluid pressure for controlling said fluid circulation; inertia means adapted to vary the controlling effect of the aforementioned means in response to and proportionately with accelerations in the movements of the shock absorber; a governor for said inertia means; and a manually operated means for controlling the governor to vary its regulating eflect upon the inertia means.

FREDERICK D. FUNSTON. 

